The present invention is generally related to a method and apparatus for connecting electrical circuits. More specifically, the present invention is related to a method and apparatus for connecting branch circuits to cores of a live electrical cable.
From the previously known German Pat. No. DE-GM-1 855 753, a known branch terminal for a ground cable exhibits two semi-circular shaped insulation bodies. Contact pieces including lugs having a conical or pyramid shape are implanted in the interior of the insulation bodies. The insulation parts are pressed together by a tension band extending around a circumferential groove in the insulation parts. A disadvantage of this arrangement is that the connection of the branch terminals is not possible at the individual contact pieces, separated from the insulation bodies. Thus, because of the required bending and insertion of branch conductors into the openings of the contact pieces, the connection of the branch circuits becomes more difficult. In addition, the exertion of pressure upon the contact pieces and the pressing of the contact piece protrusions into the cable cores requires massive upper and lower parts, thus resulting in an unnecessary manufacturing cost. Finally, the pressing of the radial contact piece protrusions during the process of pressing together the two-part insulation body is not efficient.
From the prepublication version of German Patent Document No. DE-PS-1 765 242 it is furthermore known that a branch terminal can be provided with a two-part clamping body whose two parts are kept flexible with respect to each other and which can be pressed together by the use of bolts. The clamping body parts accept the contact pieces firmly. They thus transmit to the contact pieces the pressure generated as a result of the tightening operation, and press the blades of the contact pieces, which extend in the direction of the approaching clamp body parts, into the cable cores. It is a disadvantage of this known branch terminal that the connection of the branch conductors is only possible at the contact pieces which are located within the clamp body. This makes the connection of the branch conductor more difficult. Moreover, the clamp body in this instance, due to the transfer of pressure on the contact pieces, must also consist of compact parts which are expensive to produce.
The invention is based on the objective of facilitating the connection of branch conductors to the contact pieces and simplifying the production and manufacture of the clamp body.
The invention achieves this objective with the characteristic properties which are more fully described in the specification.
One advantage of the invention is that it makes possible the connection of branch conductors, even singly, to the spatially separated contact pieces of the branch terminal. The installation process is thereby simplified considerably.
Moreover, it is possible to use a relatively simple body for pressing together the cable cores and thus, for compressing the contact blades or similar elements of the contact pieces into the cable cores.
The clamping ring, which exerts pressure only upon the cable cores, can be made from a metallic part, preferably a pressed metal ring, which is bent into a U-shaped element.
Additional advantages of the invention are evident from the following detailed description.